82 research outputs found

    DNA-dependent targeting of cell nuclei by a lupus autoantibody

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    A nuclear-penetrating lupus anti-DNA autoantibody, 3E10, has been found to inhibit DNA repair and selectively kill certain cancer cells that are highly vulnerable to DNA damage. In addition, a 3E10 single chain variable fragment (scFv) has been developed for use as a delivery vehicle to carry therapeutic cargo proteins into cell nuclei. A greater understanding of the mechanism by which 3E10 penetrates cell nuclei is needed to help determine the scope of its potential therapeutic applications. Here we show that the presence of extracellular DNA significantly enhances the nuclear uptake of 3E10 scFv. In addition, we find that 3E10 scFv preferentially localizes into tumor cell nuclei in vivo, likely due to increased DNA in the local environment released from ischemic and necrotic regions of tumor. These data provide insight into the mechanism of nuclear penetration by 3E10 and demonstrate the potential for use of 3E10 in therapeutic approaches to diseases ranging from malignancy to ischemic conditions such as stroke

    Human GM-CSF primes neutrophils for enhanced oxidative metabolism in response to the major physiological chemoattractants

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    Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a T cell- derived lymphokine which induces hematopoietic precursor cells to proliferate in vitro and differentiate to neutrophils and macrophages. GM-CSF also inhibits the motility of mature neutrophils (NIF-T activity), and primes neutrophils to enhance oxidative metabolism in response to the bacterial chemoattractant, N-formyl-methionyl-leucyl- phenylalanine (f-MLP). The present study was designed to determine whether this lymphokine also enhances neutrophil oxidative metabolism in response to the other major physiological chemoattractants which include complement-derived C5a, and the 5-lipoxygenation product of arachidonic acid, leukotriene B4 (LTB4). Superoxide anion production was measured as superoxide dismutase-inhibitable cytochrome C reduction. Purified biosynthetic GM-CSF enhanced superoxide anion production by neutrophils in response to f-MLP, C5a desArg, and LTB4. In contrast to several other factors which prime neutrophils, GM-CSF did not prime for an enhanced oxidative response to phorbol myristate acetate (PMA). These results suggest that GM-CSF may be an endogenous regulator of neutrophil inflammatory responses induced by the major physiological chemoattractants.</jats:p

    Granulocyte-macrophage colony-stimulating factor enhances phagocytosis of bacteria by human neutrophils

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    Abstract In order to determine whether human granulocyte-macrophage colony- stimulating factor (GM-CSF) can enhance phagocytosis, neutrophils were combined with Staphylococcus aureus (S aureus), and both the number of bacteria per neutrophil and the percent of neutrophils phagocytizing were assessed in the absence and presence of GM-CSF. Exposure to GM-CSF did not enable neutrophils to ingest unopsonized bacteria. When bacteria were opsonized with serum, both the number of bacteria per neutrophil and the percent of cells phagocytizing were increased by treatment with GM-CSF. Digestion of extracellular organisms by lysostaphin was used to substantiate phagocytosis. These results indicate that another effect of GM-CSF on the mature neutrophil is the enhancement of phagocytosis.</jats:p

    Human GM-CSF primes neutrophils for enhanced oxidative metabolism in response to the major physiological chemoattractants

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    Abstract Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a T cell- derived lymphokine which induces hematopoietic precursor cells to proliferate in vitro and differentiate to neutrophils and macrophages. GM-CSF also inhibits the motility of mature neutrophils (NIF-T activity), and primes neutrophils to enhance oxidative metabolism in response to the bacterial chemoattractant, N-formyl-methionyl-leucyl- phenylalanine (f-MLP). The present study was designed to determine whether this lymphokine also enhances neutrophil oxidative metabolism in response to the other major physiological chemoattractants which include complement-derived C5a, and the 5-lipoxygenation product of arachidonic acid, leukotriene B4 (LTB4). Superoxide anion production was measured as superoxide dismutase-inhibitable cytochrome C reduction. Purified biosynthetic GM-CSF enhanced superoxide anion production by neutrophils in response to f-MLP, C5a desArg, and LTB4. In contrast to several other factors which prime neutrophils, GM-CSF did not prime for an enhanced oxidative response to phorbol myristate acetate (PMA). These results suggest that GM-CSF may be an endogenous regulator of neutrophil inflammatory responses induced by the major physiological chemoattractants.</jats:p

    Granulocyte-macrophage colony-stimulating factor enhances phagocytosis of bacteria by human neutrophils

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    In order to determine whether human granulocyte-macrophage colony- stimulating factor (GM-CSF) can enhance phagocytosis, neutrophils were combined with Staphylococcus aureus (S aureus), and both the number of bacteria per neutrophil and the percent of neutrophils phagocytizing were assessed in the absence and presence of GM-CSF. Exposure to GM-CSF did not enable neutrophils to ingest unopsonized bacteria. When bacteria were opsonized with serum, both the number of bacteria per neutrophil and the percent of cells phagocytizing were increased by treatment with GM-CSF. Digestion of extracellular organisms by lysostaphin was used to substantiate phagocytosis. These results indicate that another effect of GM-CSF on the mature neutrophil is the enhancement of phagocytosis.</jats:p
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